Coupling solid phase microextraction to complementary separation platforms for metabotyping of E. coli metabolome in response to natural antibacterial agents

Abstract

The final publication is available at Springer via http://dx.doi.org/10.1007Springer via http://dx.doi.org/10. /s11306-016-1111 2 Introduction. Essential oils are known to possess antimicrobial activity; thus, their use has played an important role over the years in medicine and for food preservation purposes.Objective. The effect of clove oil and its major constituents as bactericidal agents on the global metabolic profiling of E. coli bacteria was assessed by means of metabolic alterations, using solid phase microextraction (SPME) as a sample preparation method coupled to complementary analytical platforms.Method. E. Coli cultures treated with clove oil and its major individual components were sampled by HS-SPME-GCxGC-ToF/MS and SPME-UPLC-MS. Full factorial design was applied in order to estimate the most effective antibacterial agent towards E. coli. Central composite design (CCD) and factorial design were applied to investigate parameters influencing metabolite coverage and efficiency by SPME. Results. The metabolic profile, including 500 metabolites identified by LC-MS and 789components detected by GCxGC-ToF/MS, 125 of which were identified as dysregulated metabolites, revealed changes in the metabolome provoked by the antibacterial activity of clove oil, and in particular its major constituent eugenol. Analyses of individual components selected using Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) showed a neat differentiation between control samples in comparison to treated samples in various sets of metabolic pathways.Conclusions. The combination of a sample preparation method capable of providing cleaner extracts coupled to different analytical platforms was successful in uncovering changes in metabolic pathways associated with lipids biodegradation, changes in the TCA cycle, amino acids, and enzyme inhibitors in response to antibacterial treatment.

Review of geometries and coating materials in solid phase microextraction: Opportunities, limitations, and future perspectives

“…The particle loaded blades prepared by spray coating method were employed for extraction of wide range of compounds in complex matrices such as bio-fluids [221] and metabolomics [222][223][224], in vivo and ex vivo studies [225]. For instance, Mousavi et al [222] applied spraying method for preparation different coating materials using variety of particles including C18,…”

Direct immersion solid-phase microextraction analysis of multi-class contaminants in edible seaweeds by gas chromatography-mass spectrometry

“…The 41 contaminants evaluated were distributed in classes of hydrophilic and lipophilic compounds due to their diverse affinities for the SPME coating, as already described in previous work [40]. However, in contrast to the abovementioned work [40], the currently presented work included an evaluation of the response of each compound, as opposed to an evaluation of the sum of signals pertaining to the targeted analytes. When only the sums of analyte signals are considered, individual information regarding each compound can be missed, especially in cases where there is high intensity variability among the targeted analytes.…”

The role of sample preparation in multidimensional gas chromatographic separations for non‐targeted analysis with the focus on recent biomedical, food, and plant applications

“…Mousavi et al. reported the use of HS‐SPME to successfully follow metabolic changes of E. coli induced by natural antibacterial agents such as clove oil and eugenol in real‐time and in vivo [68]. The treatment of E. coli with clove oil induced a dysregulation of 125 volatile metabolites, among which derivatives formed along with the fatty acid biosynthetic pathways, such as alcohols, ketones, and esters, were the most affected.…”